Editing Karl Popper (section)

=== Rationality ===
Popper held that rationality is not restricted to the realm of empirical or scientific theories, but that it is merely a special case of the general method of criticism, the method of finding and eliminating contradictions in knowledge without ad-hoc measures. According to this view, rational discussion about metaphysical ideas, about moral values and even about purposes is possible. Popper's student [[William W. Bartley|W.W. Bartley III]] tried to radicalise this idea and made the controversial claim that not only can criticism go beyond empirical knowledge but that everything can be rationally criticised.

To Popper, who was an anti-[[justificationism|justificationist]], traditional philosophy is misled by the false [[principle of sufficient reason]]. He thinks that no assumption can ever be or needs ever to be justified, so a lack of justification is not a justification for doubt. Instead, theories should be tested and scrutinised. It is not the goal to bless theories with claims of certainty or justification, but to eliminate errors in them. He writes,
{{blockquote|[T]here ''are'' no such things as good positive reasons; nor do we need such things [...] But [philosophers] obviously cannot quite bring [themselves] to believe that this is my opinion, let alone that it is right. (''The Philosophy of Karl Popper'', p.&nbsp;1043)}}